title: Intensity oscillations in the carbon 1s ionization cross sections of 2-butyne.
abstract: Carbon 1s photoelectron spectra for 2-butyne (CH3C≡CCH3) measured in the photon energy range from threshold to 150 eV above threshold show oscillations in the intensity ratio C2,3/C1,4. Similar oscillations have been seen in chloroethanes, where the effect has been attributed to EXAFS-type scattering from the substituent chlorine atoms. In 2-butyne, however, there is no high-Z atom to provide a scattering center and, hence, oscillations of the magnitude observed are surprising. The results have been analyzed in terms of two different theoretical models: a density-functional model with B-spline atom-centered functions to represent the continuum electrons and a multiple-scattering model using muffin-tin potentials to represent the scattering centers. Both methods give a reasonable description of the energy dependence of the intensity ratios.
authors.affiliation: Division of Natural Sciences, Keuka College, Keuka Park, New York 14478, USA.
authors.forename: Thomas X
authors.initials: TX
authors.lastname: Carroll
authors.forename: Maria G
authors.initials: MG
authors.lastname: Zahl
authors.forename: Knut J
authors.initials: KJ
authors.lastname: Børve
authors.forename: Leif J
authors.initials: LJ
authors.lastname: Sæthre
authors.forename: Piero
authors.initials: P
authors.lastname: Decleva
authors.forename: Aurora
authors.initials: A
authors.lastname: Ponzi
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Kas
authors.forename: Fernando D
authors.initials: FD
authors.lastname: Vila
authors.forename: John J
authors.initials: JJ
authors.lastname: Rehr
authors.forename: T Darrah
authors.initials: TD
authors.lastname: Thomas
mesh_terms: D002244:Carbon / Q000737:chemistry*; D004583:Electrons; D007477:Ions / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D017785:Photons; D012542:Scattering, Radiation
chemical_list: D007477:Ions; D002244:Carbon